Field of the Invention
The present invention relates to electrical components and, particularly, to SAW components operating with surface acoustic waves. Electrically conductive structures are disposed on a substrate and encapsulated, i.e., sealed against environmental influences, by a cap cover. The SAW component is provided with a cover metallization which acts as an RF shield. The invention further relates to a method for producing such as component.
An earlier, commonly owned application No. 08/743,540(see international published application WO 95/30276) describes an encapsulation for electronic components with a cap that seals component structures on a substrate. The cap is formed by a cover which is provided on the substrate and has cutouts accommodating the component structures in regions thereof.
Such an encapsulation protects the component structures against environmental influences, with the result that electronic components encapsulated in such a way can be used directly in further applications, without the need for an additional housing.
When such components are fitted in a ceramic casing and the casing is sealed with glass solder for cost reasons, then the component is not effectively RF shielded since the cover is then composed of ceramic and there is no conductive connection to the cover. When the casing is formed of plastic material, then an analogous situation results.
German published non-prosecuted patent application DE 31 38 743 A1 discloses a SAW filter enclosed in a metallic casing and sealed on all sides which avoids the above disadvantages.